Avalanche Forecast

Issued: Apr 19th, 2014 9:21AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Deep Persistent Slabs.

rbuhler, Avalanche Canada

Northwest Inland.

This bulletin was created using very limited field data. If you are out in the mountains, please send your observations to forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Generally unsettled conditions are expected for the next three days and there may a lot of variation in conditions across the region. There is also uncertainty in the weather models regarding timing and amounts of precipitation. It currently looks like Sunday should be mostly dry with light precipitation expected for Sunday night. Monday should be mostly dry before more precipitation Monday night. A ridge of high pressure looks to build late-Tuesday or Wednesday.Sunday/Sun. Night: Precipitation 1-4mm, freezing level am: 1100m pm: 1500m, ridgetop wind: moderate SE-SWMonday: A mix of sun and cloud, light scattered precipitation, freezing level am: 1000m pm: 1400m, ridgetop wind: light variableMon. Night: Precipitation 5-10mm, ridgetop wind: light SETuesday: Precipitation 1-4mm, freezing level am: 1000m pm: 1400m, ridgetop wind: light variable

Avalanche Summary

Reports from the north end of the region on Friday include sluffing from steep sun exposed slopes and isolated slab releases from leeward features on ridge crests.

Snowpack Summary

The new snow may sit on a melt-freeze crust, old wind slabs in leeward features, or dry snow in sheltered north facing terrain at higher elevations. Recent strong S through W winds have created wind slabs in leeward features. In some areas, there may still be a weak layer below the old storm snow, down roughly 50-80cm, but triggering of this layer has become stubborn or unlikely. Cornices are also large and potentially weak, particularly during periods of warming. The early February persistent weak layer is typically down 1.5 to 2m. Triggering of this layer has become unlikely but may still be possible with heavy triggers such as cornice falls or smaller avalanches stepping-down.

Problems

Wind Slabs

Wind slabs are have formed in leeward features from recent snowfall and moderate-strong S-SW winds. Storm slabs may be a concern areas which received higher snowfall amounts.

Avoid freshly wind loaded features.>The new snow will require several days to settle and stabilize.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

A deeply buried persistent weak layer still has the potential to produce very large avalanches and could still be triggered by heavy triggers such as cornice falls or smaller avalanches stepping-down.

Conditions have improved, but be mindful that deep instabilities are still present.>Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>Exercise caution on steep, unsupported slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 5

Valid until: Apr 20th, 2014 2:00PM